Piston



May 19, 19 2- c. M. PUMPHREY PISTON Filed March 10, '1941 INVENTOR.

ATTORNEYS Patented .May 19 1942 I Units as PATENT OF-FlCE rrs'rou Charles M. Pumphrey, mton, Tex. Application March 10, worsens! No. 382,645 2 Claims. ((130%) a close fit between the piston and its cylinder of the piston on which the packing ring is mounted, insuring a close fit between the piston and its cylinder, and eliminating any possibility of the packing ring bending rearwardly on the. power stroke.

A still further object of the invention is to pro vide means for permitting horizontal and vertical play of the piston within its cylinder, without efiectlng the seal between the piston and cylinder. Another important object of the invention is to provide a flexible piston packing having a flexible steel bracing member embedded therein, the bracing member being designed to permit flexibility oi the packing and at the same time lend rigidity to the packing, increasing the wear qualities of the packing.

With the foregoing and other objects in View, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein described, may be made within the scope of what is claimed, without departing from the spirit of the invention.

Referring to the drawing:

Figure 1 is a longitudinal sectional view through a piston constructed in accordance with the invention, and illustrating the piston as moving in a cylinder.

Figure 2 is a sectional view taken on line 2-2 of-Figure l.

Referring to the drawing in detail, the reference character 5 designates the piston rod, which is formed. with an enlargement b disposed in spaced relation with the free end of the rod, the 68 from the straight surface 9 adjacent thereto, I

enlargement 6 providing an abutment for one end of the piston. I V

The piston comprises a body portion '8 which is of a diameter appreciably less than the diameter of the cylinder in which it moves, providing a wide space between the piston and cylinder wall.

The ends of the body portion are tapered inwardly, providing inclined surfaces or seats for the packing rings 8. mounted at each end of the body portion.

As clearly shown by Figure 1 of the drawing, the inclined end walls of the body portion, have their outer ends spaced from the periphery of the body portion, providing substantially straightsurfaces 9 at the ends of the body portion.

At each end of the body portion I, is a packing ring lb constructed of suitable wear-resisting material,- preferably rubber. These packing rings are molded around flexible steel disk-like members ll formed with rolled outer ends it, to reduce wear at the ends of the body portion, of the packing rings, to the minimum. Openings are formed in the flexible steel members, and when the wear-resisting material is molded around the members, the flexible wear-resisting material will find its way into the openings, securing the members in position.

The outer or cylinder-engaging edges of the packing ring It, are of a construction to permit of free sliding movements of the packing rings,

but at the same time eliminate any possibility of the packing rings folding rearwardly on the power stroke of the piston.

As shown, the cylinder-engaging surfaces of the packing rings are enlarged and curved, as at l3. I

The packlngs rings l8, are held in position on the body portion I,'by the disks H which are shaped to-conform to the recessed ends of the body portion. The disks l4 are of diameters less than the diameter of the piston, providing ample space at the ends of the piston to allow the rings H) to flex freely. .One end of the piston rod 5 is threaded to receive the nuts to,

which, when properly positioned, direct pressure to the disks |3,clamping the packing rings onto the body portion.

From the foregoing it will be seen that due to the construction shown and described, a packing ring on th pumping stroke will move rearwardly against the straight surface 9 of the body portion I, insuring a close flt between the packing ring and cylinder wall. The packing ring at the opposite end will of course move away permitting of free flexing of the packing ring to permit foreign matter which may collect between the ring and cylinder wall, to fall away from the cylinder wall. Upon the return movement of the piston, the rings will move in the opposite directions providing a close fit between the ring and cylinder wall, while the ring at the opposite end of the body portion moves away from the 2. Ina pump for pumping semi-solid material, a pump cylinder, 9. piston comprising abody portion having inclined recessed end walls, terminating in substantially straight flat surfaces providing shoulders adjacent to the periphery of the piston, flexible packing rings fitted over the inclined end walls, the outer edges thereof extending an appreciable distance beyond the periphery of the piston, portions of the packing rings adjacent to the free edges thereof being substantially thick, a disk-like steel member embedded in each packing ring, the outer edges of the disk-like steel members terminating at points where the thickened portions of the packing rings merge into the main portions of the packing rings, the thickened portions of the packing rings adapted to rest against the shoulders on one stroke of the piston, and means for securing the packing rings to the inclined end walls of the disk-like member embedded in said packing rings 20 piston.

and adapted to hold the packing rings substantially rigid, against the wall of the cylinder, and disks for securing the packing rings to the ends of the piston.

, CHARLES M. PUMPHREY. 

